Process for breaking petroleum emulsions



Patented July 29, 1952 PROCESS FOR BREAKING PETROLEUM EMULSION S Melvin De Groote, St. Louis, Mo., assignor to Petrolite Corporation, Ltd., Wilmington, Del., a corporation of Delaware No Drawing. Application February 8, 1952, Serial No. 270,768

9 Claims. (01. 252-341) This invention relates to petroleum emulsions of the watersin-oil type that are commonly referred to as cut oil, roily oil, emulsified 'oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanentstate throughout the oil which constitutes the continuous phase of the emulsion.

One object of my invention is to provide a novel process for breaking or resolving emulsions of the kind referred to.

Another object of my invention is to provide an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft Waters or weak brines. Controlled emulsification and subsequent demuls'ification under the conditions just mentioned, are of significant value in removing impurities particularly inorganic salts from pipeline oil.

Demulsification as contemplated in the present application includes the preventive step of commingling the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion, in absence of such precautionary measure. Similarly, such demulsifier may be mixed with the hydrocarbon component.

The demulsifying agent employed in the present process is the fractional ester obtained from a polycarboxy acid and a nitrogen-containing diol obtained by the oxypropylation of a primary amine having not more than 7 carbon atoms and containing a phenyl radical. 'For all practical purposes this limits the amine to aniline, benzylamine, and a toluidine, such as orthotoluidine. Furthermore, the dihydroxylated compound prior to esterification must be water-insoluble and kerosene-soluble. Momentarily ignoring certain variants of structure which will be considered and preferably free from any radicals having more than 8 uninterrupted carbon atoms in a single group, and with the further proviso that the parent dihydroxy compound prior to esterificationbe water-insoluble and kerosene-soluble.

The present application is a continuation-inpart of my copending application Serial No. 183,294, filed September 5, 1950, now abandoned.

Attention is directed to the C. M. Blair, Jr., Patent No. 2,562,878, dated August 7, 1951, the application for which was copending with my application Serial No. 183,294 noted above and, in which there is described, among other'things, a process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of an esterification product of a dicarboxylic acid and a polyalkylene glycol in which the ratio of equivalents of polybasic acid to equivalents of polyalkylene glycol is in the range of 0.5 to 2.0, in which the alkylene group has from 2 to 3 carbon atoms, and in which the molecular weight of the product is between 1,500 to 4,000.

Similarly, there have been used esters of dicarboxy acids and polypropylene glycols in which 2 moles of the dicarboxy acid ester have been reacted with one mole of a polypropylene glycol having a molecular weight, for example, of 2,000 so as to form an acidic fractional ester. Examination of what is said subsequently herein as well as the hereto appended claims in comparison with the previous example will show the line of delineation between such somewhat comparable compounds. Of greater significance, however, is What is said subsequently in regard to the structure of the parent diol as compared to polyprosubsequently the demulsifier may be exemplified phenyl radical, or the benzyl radical, and n and n are whole numbers with the proviso that n plus n equals a sum varying from 15 to 80; n

is a whole number not over 2 and R is the radical of the polycarboxy acid plene glycols whose molecular weights may vary from 1,000 to 2,000.

The cheapest of the three amines which can be employed is aniline and this is my preferred reagent. The oxypropylation of aniline is well known although I am not aware that aniline (or for that matter a toluidine or benzylamine) has ever been oxyalkylated with propylene oxide so as to yield a product which is water-insoluble and kerosene-soluble.

For convenience, what is said hereinafter will be divided into five parts:

Part 1 is concerned with the preparation of the oxypropylation derivatives of the specified amines;

Part 2 is concerned with, the preparation of the esters from the oxypropylated derivatives;

Part 3 is concerned with the structure of the oxypropylation products obtained from the specified amines. Insofar that such materials tives are obtained by modest oxyethylation preceding the oxypropylationstep, or oxypropylation followed by oxyethylation. This results in diols having somewhat difierent properties which can then be reacted with the, same polycarboxy acids or anyhdrides described in Part 2"to give. efiective dcmulsifying agents. description of the apparatus makes casual men'- tion of oxyethylation. For the same reason there is brief mention of the use of glycide.

PART 1 For a number of well known reasons equipment, whether laboratory size, semi-pilot plant size, pilot plant size, or large scale size, is not as a rule designed for a particular alkylene oxide. Invariably and inevitably, however, or particularly in the case of laboratory equipment and range, such as to pounds.

t to large-scale operations. I have used conven tional equipment with two added automatic features; (a) a solenoid controlled valve which shuts off the propylene oxide in event that the temperature gets outside a predetermined and set range, for instance, 95to 120 C., and (b) another solenoid valve which shuts off the propylene oxide (or for that matter ethylene oxide if it is being used) if the pressure gets beyond a predetermined Otherwise, the equipment is substantially the same as is com- 4 monly employed-for this purpose where the pressure of reaction is higher, speed of reaction is higher, and time of reaction is much shorter. In such instances such automatic controls are not necessarily used.

For thisreason a pilot plantsize the design is such as to use.. any

of the customarily. available alkylene oxide,-.i.e., ethylene oxide, propylene oxide, butylene' oxide, glycide,epichlorohydrin, styrene oxide, etc. In thesubsequent description of the equipment it becomes obvious that it is adapted foroxyethylation as well asoxypropylation.

Oxypropylations are conducted under a wide variety of conditions, not only in regard to presence or. absence of catalyst, and the kind ofcatalyst, but also in regard to the time of reaction, 1-.

temperature of reaction, speed of reaction, press sure during reaction, etc. .For instance, oxyalkylations can be conducted at temperatures up to approximately 200 C. with pressures. inabout the same range up to about 200 pounds per square inch. They can be conducted also at temperatures approximating the-boiling point of water or slightly above, as for example 95 to 120 C. Under such circumstances the pressurewill be less than 30 pounds per square inch unless some special procedure is employed asis sometimes the case, to wit, keeping an atmosphere of inert gas such as nitrogen in the vessel during the reaction, fiuch low-temperature-low-reaction rate oxypropylations have been described very completely in U. S. Patent No. 2,448,664, to H. R. Fife et al., dated September 7, 1948. Low to i.- perature, low. pressure oxypropylations are particularly desirable where the compound being subjected to oxypropylation contains one, two or threepoints of reaction only, such as monohydric alcohols, glycols and triols.

Although the word glycol or diol is usually applied to compounds containing carbon, hydrogen, and oxygen only, yet the nitrogen-containing compounds herein are diols in the sense that they are dihydroxylated. Thus, the conditions which apply to the oxypropylation of certain glycols also apply in this instance. 1

Since low-pressure-iow-temperature reaction speed oxypropylations require considerable time, for instance, 1 to '7 days of '24 hours each tocomplete the reaction they are conducted as a rule whether on. a laboratory scale; pilot plant scale, or large scale, so; as to operate automatically. The prior figure'of' seven days applies especially Thus, in preparing the various examples I have found it particularly advantageous to use laboratory equipment or pilot plant which is designed to permit continuous oxyalkylation whether it be oxypropylation or oxyethylation. With certain obvious changes the equipment can be used also to permit oxylalkylation involving the use of glycide where no pressure is involved except the vapor pressure of asolvent, if any, which may have been used as a diluent.

As previously pointed out the method of using propylene oxide is the same as ethylene oxide. This point is emphasized only for the reason that the apparatus is so designed and constructed as to use either oxide The oxypropylation procedure employed in the preparation of the oxyalkylated. derivatives has been uniformly the same, particularly in light of the fact that a continuous automatically-controlled procedure was employed. In this procedure the autoclave was a conventional auto:- clave made of stainless steel and having a capacity otapproximately 15 gallons and a working pressure of one thousand pounds gauge pressure. This pressure obviously is far beyond any requirement as far as propylene oxide. goes unless there is a reaction of explosive violence involved. due to accident. The autoclave was equipped with the conventional devices and openings, such as the variable-speed stirrer operating at speeds from 50 R. P. M. to 500 R. P..M.; thermometer well and thermocouple for mechanical. thermometer; emptying outlet; pressure gauge, manual ventline; charge hole for initial reactants; at least one connection for introducing the alkylene oxide, such as propylene oxide or eth 'lene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and, preferably, coils in addition thereto, with the jacket so arranged that it is suitable for heating with steam or cooling with water and furtherv equipped with electrical heating devices. Such autoclaves are, of course, in essence small-scale replicas of the usual conventional autoclave used in oxyalkylation procedures. In some instances in exploratory preparations an autoclave having a smaller capacity, for instance, approximately 3 liters in one case and about 1% gallons in another case, was

used. v V

Continuous operation, or substantially con: tinuous operation, was achieved by the use of a separate container to hold the alkylene oxide being employed, particularly propylene oxide. In conjunction with the smaller autoclaves, the container consists essentially of a laboratory bomb having a capacity of about one-half gallon, or somewhat in excess thereof. In some of time, for instance, 4 to 5 hours.

instances a larger bomb was used, to wit, one having a capacity of about one gallon. This bomb was equipped, also, with an inlet for charging, and an eductor tube going to the bottom of the container so as to permit discharging of alkylene oxide in the liquid phase to the autoclave. A bomb having a capacity of about 60 pounds was used in connection with the -gallon autoclave. Other conventional equipment consists, of course, of the rupture disc, pressure gauge, sight feedglass, thermometer, connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. The connections between the bomb and the autoclave were flexible stainless steel hose or tubing so that continuous weighings could be made without breaking or making any connections. This applies also to the nitrogen line, which was used to pressure the bomb reservoir. To the extent that it was required, any other usual conventional procedure or addition which provided greater safety was used, of course, such as safety glass protective screens, etc.

Attention is directed again to what has. been said previously in regard to automatic controls which shut oif the propylene oxide in event temperature of reaction passes out of the predetermined range or if pressurein the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations become uniform in that the reaction temperature was held within a few degrees of any selected point, for instance, if 105 C. was selected as the operating temperature the maximum point would be at the most 110 C. or 112C., and the lower point would be 95 or possibly 98 C. Similarly, the pressure was held at approximately 30 pounds within a 5-pound variation one way or the other, but might drop to practically zero, especially where no solvent such as xylene is employed. The speed of reperature, for instance, between 150 to 200 C., an unreacted alkylene oxide such as propylene oxide, makes its presence felt in the increase in pressure or the consistency of a higher pressure. However, at a low enough temperature it may happen that the propylene oxide goes in as a liquid. If so, and if it remains unreacted there is, of course, an inherent danger and appropriate steps must be taken to safeguard against this possibility; if

need be a sample must be withdrawn and examined forunreacted propylene oxide. One obvious procedure, of course, is to oxypropylate at a modestly higher temperature, for instance, at 140 to 150 C. Unreacted oxide affects determination of the acetyl or hydroxyl value of the hydroxylated compound obtained.

' The higher the molecular weight of the compound, i. e., towards the latter stages of reaction, the longer the time required to add a given amount of oxide. One possible explanation is that the molecule, being larger, the opportunity for random reaction is decreased. Inversely, the lower the molecular weight the faster the reaction takes place. For this reason, sometimes at least, increasing the concentration of the catalyst does not appreciablyspeed up the reaction, particularly when the product subjected to oxyalkylation has a comparatively high molecular weight. However, as has been pointed out previously, operating at a low' pressure and a low temperature even in large scale operations as much as a week or ten days time may lapse to obtain some of the higher molecular weight derivatives from monohydric or dihydric materials.

In a number of operations the counterbalance scale or dial scale holding the propylene oxide action was comparatively slow under such conditions as compared with oxyalkylations at 200 C; Numerous reactions were conducted in which the time varied from one day (24 hours) up to three days ('72 hours), for completion of-the final member of aseries. In some instances the reaction may take place in considerably less time, i.'e'., 24 hours or less, as faras a partial oxypropylation is concerned. The minimum time recorded was about a 3-hour period in a single step. Reactions indicated as being complete in 10 hours may have been completed in a lesser period of time in light of the automatic equipment employed. This applies also where the reactions were complete in a shorter period In the addition of propylene oxide, in the autoclave equipment as far as possible the valves were set so all the propylene oxide if fed continuously would be added at a rate so that the predetermined amount would react within the first 15 hours of the 24-hour period or two-thirds of any shorter period. This meant that if the reaction was interrupted automatically for a period of time for pressure to drop or temperature to drop the predetermined amount of oxide would still be added in most instances well within the predetermined time period. Sometimes where the addition was a comparatively small amount in a l0-hour period there would be an unquestionable speeding up of the reaction, by simply repeating the examples and using 3, 4, or 5 hours instead of 10 hours.

When operating at a comparatively high tembomb was so set that when the predetermined amount of propylene oxide had passed into the reaction the scale movement through a time operating device was set for either one to two hours so that reaction continued for 1 to 3 hours after the final addition of the last propylene oxide and thereafter the operation was shut down. This particular device is particularly suitable for use on larger equipment than laboratory size auto claves, to'wit, on semi-pilot plant or pilot plant size, as well as on large scale size. This final stirring period is intended to avoid the presence of unreacted oxide.

In this sort of operation, of course, the temperature range was controlled automatically by either use of cooling water, steam, or electrical heat, so as to raise or lower the temperature. The pressuring of the propylene oxide into the reaction vessel was also automatic insofar that the feed stream was set for a slow continuous run which was shut off in case the pressure passed a predetermined point as previously set out. All the points of design, construction, etc., were conventional including the gases, check valves and entire equipment. As far as I am aware at least two firms, and possibly three, specialize in autoclave equipment such as I have employed in the laboratory, and are prepared to furnish equipment of this same kind. Similarly pilot plant equipment is available. This point is simply made as a precaution in the direction of safety. Oxyalkylations, particularly involving ethylene oxide, glycide, propylene oxide, etc., should not be conducted except in equipment specifically designed for the purpose.

Eccample 1a The starting material was a commercial grade of aniline. The particular autoclave employed was one with a capacity of 15 gallons, won the average of about 1-20 pounds of reaction mass. The speed of the stirrer could be varied from 150 to 350 R. P. M. 5 pounds of aniline were charged into the autoclave along with one-half pound caustic soda. The reaction pot was flushed out with nitrogen. The autoclave was sealed and the automatic devices adjusted and set for injecting a total of 65.25. pounds of propylene oxide in approximately a -hour period. The pressure regulator was set for a maximum of 35 pounds per squareinch. This meant that thebulk of the reaction could take place, and probably didtake place, at a lower pressure. This comparatively low pressure was the result of the fact that considerable catalyst was present, and especially when one allows for the fact that aniline does have some basicity itself. The propylene oxide was added comparatively slowly, and, more important, the selected temperature range was 205 to 215 F. (about the boiling point of water). The initial introduction of propylene oxide was not started until the heating devices had raised the temperature to about the boiling point of water. At the completion of the reaction a sample was taken and oxypro'pylation proceeded as in Ex- H ample 201, immediately succeeding.

Example 2a Bi l-pounds of the reaction mass identified as Example 1a, preceding, were permitted to remain in the reaction vessel and without the addition of Example 5a Approximately 74.4 pounds of the reaction mass was permitted to stay in the autoclave. No additional catalyst was introduced. 14.0 pounds of propylene oxide were added. The time required to add this propylene oxide was 9 hours. The conditions of reaction in regard to temperature and pressure were substantially the same as in Example 1a, preceding.

In this particular series of examples, the oxypropylation was stopped at this stage. In other series I have continued the oxypropylation so that the theoretical molecular weight varied from 6,000 to 7,000 but the increase in molecular weight by hydroxyl determination was comparatively small, being 2,300 in the first case and 2,360 in the second case.

What is said herein is presented in tabular form in Table 1 immediately following, with some added information as to molecular weight and as to solubility of the reaction product in water, xylene and kerosene.

TABLE 1 Composition Before Composition at End M. W. Max Max. E N by Hyd Pres, Time, Amine Oxide Catou Theo. Amine Oxide Cata- Deter lbs. Hrs.

Amt, Amt, lyst, Mol. Amt, Amt, lyst, min sq. in.

Lbs. Lbs Lbs. Wt. Lbs. Lbs. Lbs.

5. 0 0. 50 1,305 5.00 05. 50 l, 270 2052l5 10 70 49.24 0.37 1,740 3.76 60. 49 .37 1,590 205215 d5 8 3.33 53.95 0.33 2,515 3. 33 85. 71 .33 1,744 205-2l5 35 8 2. (3. 67 0. 25 3, 820 2. 45 98. 42 25 2, 20 205-2l5 35 10 l. 80 72. 40 0. l7 4, 560 1.80 80. 40 17 2, 270 205-2l5 25 9 any more catalyst 17.25 pounds of propylene oxide were added. The oxypropylation wasconducted in substantially the same manner with regard to pressure and temperature as in Example 1a, preceding, except that the reaction was complete in slightly less time, i. e., 8 hours instead of 10 hours. At the end of the reaction period part of the sample was withdrawn and oxypropylation was continued as described in Example 3a, following.

Example 311 62.6 pounds of the reaction mass identified as Example 2c, preceding, was permitted to remain in the reaction vessel. 27.75 pounds of propylene oxide were introduced in this third stage. No additional catalyst was added. The time period required was the same as in Example 20, preceding, i. e., 8 hours. The conditions of reaction as far as temperature and pressure were concerned were substantially the same as in Example 1a, preceding. At the completion of the reaction part of the reaction mass was withdrawn and the remainder subjected to oxypropylation as described in Example 4a, following.

Example 4a 66.4 pounds of the reaction mass identified as All examples (1a through 5a.) were insoluble in water, but soluble in xylene and soluble in kerosene. This was true, also, of other samples in which the theoretical molecular weight was somewhat higher as in the instance of those examples whose theoretical molecular weight was in the 6,000 to 7,000 range.

This applied also to samples obtained in substantially the same manner from ortho-toluidine and also from benzylamine. The final product, i. e., at the end of the oxypropylation step, was a somewhat viscous, reddish-colored fluid. This was characteristic of all the various products obtained from the three amines. These products were, of course, slightly alkaline due to the residual caustic soda and also due to the basic nitrogen atom which is significant, at least in the case of benzylamine. The residual basicity due to the catalyst would, of course, be the same if sodium methylate had been. used.

Speaking of insolubility in water or solubility in kerosene such solubility test can be made simply by shaking small amounts of the materials in a test tube with water, for instance, using 1% to 5% approximately based on the amount of water present.

Needless to say, there is no complete conversion ofpropylene oxide into the desired hydroxylated compounds. This is indicated by the factthat the theoretical molecular weight base on a statistical average is greater than the molecular weight calculated by usual methods on basis of acetyl or hydroxyl value. Actually, there is no completely satisfactory method for determining molecular weights of these types of compounds with a high degree of accuracy when the molecular weights exceed 2,000. In some instances the acetyl value or hydroxyl value serves as satisfactorily as an index to the molecular weight as any other procedure, subject to the above limitations, and especially in the higher molecular weight range. If

any difficulty is encountered in the manufacture of the esters as described in Part 2 the stoichiometrical amount of acid or acid compound should be taken which corresponds to the indicated acetyl or hydroxyl value. This matter has been discussed in the literature and is a matter of common knowledge and requires no further elaboration. In fact, it is illustrated by some of the examples appearing in the patent previously mentioned.

PART 2 As previously pointed out the present invention is concerned with acidic esters obtained from the oxypropylated derivatives described in Part 1, immediately preceding, and polycarboxy acids, particularly dicarboxy acids such as adipic acid, phthalic acid, or anhydride, succinic acid, diglycollic acid, sebacic acid, azelaic acid, aconitic acid, maleic acid or anhydride, citraconic acid or anhydride, maleic acid or anhydride adducts as obtained by the Diels-Alder reaction from reactants such as maleic anhydride and cyclopentadiene. Such acids should be heat stable so they are not decomposed during esterification. They may contain as many as 36 carbon atoms as, for example, the acids obtained by dimerization of unsaturated fatty acids, unsaturated monocarboxy fatty acids, or unsaturated monocarboxy acids having 18 carbon atoms. Reference to the acid in the hereto appended claims obviously includes the anhydrides or any other obvious equivalents. My preference, however, is to use polycarboxy acids having not over 8 carbon atoms.

The production of esters including acid esters (fractional esters) from polycarboxy acids and glycols or other hydroxylated compounds is well known. Needless to say, various compounds may be used such as the low molal ester, the anhydride, the acyl chloride, etc. However, for purpose of economy it is customary to use either the acid or the anhydride. A conventional procedure is employed. On a laboratory scale one can employ a resin pot of the kind described in U. S. Patent No. 2,499,370, dated March 7, 1950, to De Groote and Keiser, and particularly with one more opening to permit the use of a porous spreader if hydrochloric acid gas is to be used as a catalyst. Such device or absorption spreader consists of minute alundum thimbles which are connected to a glass tube. One can add a sulf-onic acid such as para-toluene sulfonic acid as a catalyst. There is some objection to this because in some instances there is some evidence that this acid catalyst tends to decompose or rearrange oxypropylated compounds, and particularlylikely to do so if the esterification temperature is too high. In the case of polycarboxy acids such as diglycollic acid, which is strongly acidic there is no need to add. any catalyst. The use of hydrochloric gas has one advantage over paratoluene sulfonic acid and that is that at the end of the reaction it can be removed by flushing out with nitrogen, whereas there is no reasonably convenient means available of removing the paratoluene sulfonic acid or other sulfonic acid employed. If hydrochloric acid is employed one need only pass the gas through at an exceedingly slow rate so as to keep the reaction mass acidic. Only a trace of acid need be present. I have employed hydrochloric acid gas or the aqueous acid itself to'eliminate the initial basic material. My preference, however, is to use no catalyst whatsoever and to insure complete dryness of the diol as described in the final procedure just preceding Table 2.

The products obtained in Part 1 preceding may contain a basic catalyst. As a general procedure I have added an amount of half-concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. The mixture is shaken thoroughly and allowed to stand overnight. It is then filtered and refiuxed with the xylene present until the water can be separated in a phase-separating trap. As soon as the product is substantially free from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. If there is any further deposition of sodium chloride during the reflux stage needless to say a second filtration may be required. In any event the neutral or slightly acidic solution of the oxypropylated derivatives described in Part 1 is then diluted further with suficient xylene, decalin, petroleum solvent, or the like, so that one has obtained approximately a 65% solution. To this solution there is added a polycarboxylated reactant as previously described, such as phthalic anhydride, succinic acid or anhydride, diglycollic acid, etc. The mixture is refluxed until esterification is complete as indicated by elimination of water or drop in carboxyl value. Needless to say, if one produces a half-ester from an anhydride such as phthalic anhydride, no water is eliminated. However, if it is obtained from diglycollic acid, for example, water is eliminated. All such procedures are conventional and have been so thoroughly described in the literature that further consideration will be limited to a few examples and a comprehensive table.

Other procedures for eliminating the basic residual catalyst, if any, can be employed. For example, the oxyalkylation can be conducted in absence of a solvent or the solvent removed after oxypropylation. Such oxypropylation end product can be then be acidified with just enough concentrated hydrochloric acid to just neutralize the residual basic catalyst. To this product one can then add a small amount of anhydrous sodium sulfate (sufficient in quantity to take up any water that is, present) and then subject the mass to centrifugal force so as to eliminate the hydrated sodium sulfate and probably the sodium chloride formed. The clear somewhat viscous straw-colored amber liquid so obtained may contain a small amount of sodium sulfate or sodium chloride but, in any event, is perfectly acceptable for esterification in the manner described.

It is to be pointed out that the products here described are not polyesters in the sense that there is a plurality of both diol radicals and acid when a number of conventional procedures are used and may retard esterification, particularly where there is no sulionic acid or hydrochloric acid present as a catalyst. Therefore, I have preferred to use the following procedure: I have employed about 200 grams of the diol as described in Part 1, preceding; I have added about 60 grams of benzene, and then refluxed this mixture in the glass resin pot using a phase-separating trap until the benzene carried out all the water present as Water of solution or the equivalent. Ordinarily this refluxing temperature is apt to be in the neighborhood of 130 to possibly 150 C. When all this water or moisture has been removed I also withdraw approximately grams or a little less benzene and then add the required amount of the carboxy reactant and also about 150 grams of a high boiling aromatic petroleum solvent. These solvents are sold by various oil refineries, and, as far as solvent eiiect act as if they were almost completely aromatic in character. Typical distillation data in the particular type I have employed and found very satisfactory is the following:

tion and provided there is no objection to a little residue. Actually, when these materials are used for a purpose such as clemulsification the solvent might just as well be allowed to remain. If the solvent is to be removed by distillation, and particularly vacuum distillation, then the high boiling aromatic petroleum solvent might well be replaced by some more expensive solvent, such as decalin or an alkylated decalin which has a rather definite or close range boiling point. The removal of the solvent, of course, is purely a conventional procedure and requires no elaboration.

In the appended table solvent #7-3, which appears in all instances, is a'mixture of 7 volumes of the aromatic petroleum solvent previously described and 3 volumes of benzene. This was used, or a similar mixture, in the manner previously described. In a large number of similar examples decalin has been used but it is my preference to use the above mentioned mixture and particularly with the preliminary step of removing all the water. If one does not intend to remove the solvent my preference is to use the petroleum solvent-benzene mixture although obviously any I. B. P., 142 C. m1., 225 C. 25 of the other mixtures, such as decalin and Xylene, 5 1,, 200 c, ml, 230 C. can be employed. 101111., 209C. ml, 234 C. The data included in the subsequent tables, 15111l.,215 C. 451161.,237" C. i. e., Tables 2 and 3, are self-explanatory, and 20 ml., 216 C. ml., 242 C. very complete and it is believed no further elab- 25 ml., 220 C. ml., 244 C. 90 oration is necessary.

TABLE 2 Theo. M01. of Ex. 01 Ex.No.ci Theo. Hyg f Weight fi a P Acid Hydroxy M. W. droxyl d Y 1 Bascdon Y carbmy Ester 0111p ME. 0. v. 61 m Actual Cmpd- React V H GI Value H (Grs.) ant (G'rs.)

85.8 87.8 1,276 197 Maleic Anbydride" 30.2 85.8 87. 8 1, 276 197 Diglycollic Acid... 42. 9 85. 8 87. 8 1, 276 197 AconiticAcid 53. 5 85. 8 87.8 1, 276 197 Citraconic Acid. .0 34. 5 64. 4 70.2 1, 596 201 Diglycollic Acid 83. 8 64. 4 70. 2 1, 596 201 M8161 Anhydridc... 24. 3 64.4 70.2 1,596 201 AconiticAcid 48.8 64. 4 70. 2 1, 596 201 Citraconic Acid. 28.0 44. 6 64. 2 1, 744 198 DiglycollicAcidnu 27. 9 44. 6 64. 2 1,744 201 M81610 Anhydridc... 23. 0 44. 6 04. 2 1, 744 198 Aconitic Acid 40. 7 44.6 04.2 1,744 199 CitraconicAcid 25.5 29.3 50.8 2, 208 199 DiglycollicAcidflln 24.1 29.8 50.8 2, 208 19 PhthalicAnhydride. 26.6 29.3 50.8 2, 208 198 MaleicAnhydridc... 17.7 29.3 50.8 2,208 199 AconiticAcid 31.0 29. 3 50. 8 2, 208 200 Citraconic Acid. 20. 2 24. 6 49.2 2,270 198 DiglycollicAcid 23.4 24. 6 49.2 2, 270 199 Phthalic Anhydride. 25. 9 2 4. 6 49. 2 2,270 199 Maleic Anhydride... 17. 2 24.6 49.2 2,270 198 AconiticAcid 30.4 24. 6 49. 2 2,270 199 OltIaCOlliOACld. 19. 6

m1, 248 C. 80 ml. 64 55 TABLE 3 65 ml., 252 C. 35 11113529 C. 90 1, 230 C Amt Esterifica- Time of Water Ex. No. of s 1 t 801- T C. m1" 6 (1 Acid Ester 0 ven vent t1on emp., Estenfica- Out 7 (gm) 0. tion (hrs) (00.)

After this material is added, refluxing is continned, and, of course, is at a high temperature, 32; $2 1% g g to wit, about to C. If the carboxy re- #7-3 247 1% 5 514 actantis an anhydride needless to say no water $13 2 1? of reaction appears; if the carboxy reactant is an #7-3 222 138 5% None acid water of reaction should appear and should 1 244 157 1% #7 3 227 140 5% None be elnmnated at the above reaction temperature. iii-3 227 168 3 45 i I If 1t 18 not elimlnated I slmply separate out an- 51;; 2 other 10 to 20 cc. of benzene by means of the if; 2 None phase-separating trap and thus raise the tem- #7-3 225 143 8 2 N6 5: pera-ture to or C., or even to 200 C., if 217 147 8 #7-8 224 178 1 8.4 need be. My preference 18 not to go above about #7-3 220 178 5% None C #7-3 218 166 7 3.0 t #7-3 226 157 6% None 'The use of such solvent 18 extremely satisfac- .#7-3 216 160 554 0,3 tory provided one does not attempt to remove the $31 5 352 solvent subsequently except by vacuum distilla- 2 The procedure for manufacturing the esters has been illustrated by preceding examples. If for any reason reaction does not take place in a manner that is acceptable, attention should be directed to the following details: (a) Recheck the hydroxyl or acetyl value of the oxypropylated primary amines of the kind specified and use a stoichiometrically equivalent amount of acid; (b) if the reaction does not proceed with rea-- sonable speed either raise the temperature indicated or else extend the period of time up to 12 or 16 hours if need be; (c) if necessary, use A;% of paratoluene sulfonic acid or some other a'cid as a catalyst; (d) if. the esterification does not produce a clear product a check should be made to see if an inorganic salt such as sodium chloride or sodium sulfate is not precipitating out. Such salt should be eliminated, at least for exploration experimentation, and can be removed by filtering. Everything else being equal as the size of the molecule increases the reactive hydroxyl radical represents a smaller fraction of the entire molecule and thus more difficulty is involved in obtaining complete esterification.

Even under the most carefully controlled conditions of oxypropylation involving comparatively low temperatures and long time of reaction there are formed certain compounds whose-composition is still obscure. Such side reaction products can contribute a substantial proportion of the final cogeneric reaction mixture. Various suggestions have been made as to the nature of these compounds, such as being cyclic polymers of propylene oxide, dehydration products with the appearance of a vinyl radial or isomers of propylene oxide or derivatives thereof, i.e., of an aldehyde, ketone, or allyl alcohol. In some instances an attempt to react the stoichiometric amount of a polycarboxy acid with the oxypropylated derivative results in an excess of the carboxylated reactant for the reason that apparently under conditions of reaction less reactive hydroxyl radicals are present than indicated by the hydroxyl value. Under such circumstances there is simply a residue of the carboxylic reactant which can be removed by filtration or, if desired, the esterification procedure can be repeated using an appropriately reduced ratio'of carboxylic reactant.

Even the determination of the hydroxyl value and conventional procedure leaves much to be desired due either to the cogeneric materials previously referred to, or for that matter, the presence, of any inorganic salts or propylene oxide. Obviously this oxide should be eliminated.

The solvent employed, if any, can be removed from the finished ester by distillation and particularly vacuum distillation. The final products or liquids are generally pale reddish amber to reddish amber in color, and show moderate viscosity. They can be bleached with bleaching clays, filtering chars, and the like. However, for the purpose of demulsification or the like color is not a factor and decolorization is not justified.

In the above instances I have permitted the solvents to remain present in the final reaction mass. In other instances I have followed. the same procedure using decalin or a mixture of decalin or benzene in the same manner and ultimately removed all the solvents by vacuum distillation. Appearances of the final products are much the same as the diols before esterification and in some instances were somewhat darker in color and had a more reddish cast and perhaps somewhat more viscous.

- interfaces.

' instances.

14 PART 3 Previous reference has been made to the fact that diols (nitrogen-free compounds) such as polypropyleneglycol of approximately 2,000 molecular weight, for example, have been esterified with di-carboxy acids and employed as demulsifying agents. The herein described compounds are different from such diols although both, it is true, are high molecular weight dihydroxylated compounds. The instant compounds have present a nitrogen atom which is at least somewhat basic in the case of aniline or a comp-arable compound having a methyl group in the benzene ring. When derived from benzylamine such compounds have an unquestionably basic nitrogen atom present. In any event, even a nitrogen atom of low basicity probably infiuences the orientation of acidic molecules at Stated another way, the ultimate ester has as least two free carboxyl radicals. It seems reasonable to assume that the orientation of such molecules at an oil-water interface, for example, are affected by the presence of a nitrogen atom having significant or definite basicity. Regardless of what the difference may be the fact still remains that the compounds of the kind herein described may be, and frequently are, 10%, 15% or 20% better on a quantitative basis than the simpler compound previously described, and demulsify faster and give cleaner oil in many The method of'making such comparative tests has been described in a booklet entitled Treating Oil Field Emulsions, used in the Vocational Training Course, Petroleum Industry Series, of the American Petroleum Institute.

It may be well to emphasize also the fact that oxypropylation does not produce a single compound but a cogeneric mixture. The factor involved is the same as appears if one were oxypropylating a monohydric alcohol or a glycol. Momentarily, one may consider the structure of a polypropylene glycol, such as polypropylene glycol of 2000 molecular weight. Propylene glycol has a primary alcohol radical and a secondary alcohol radical. In this sense the building unit which forms polypropylene glyools is not symmetrical. Obviously, then, polypropylene glycols can be obtained, at least theoretically, in which two secondary alcohol groups are united or a secondary alcohol group is united to a primary alcohol group, etherization being involved, of course, in each instance.

Usually no effort is made to differentiate between oxypropylation taking place, for example, at the primary alcohol unit radical or the secondary alcohol radical. Actually, when such products are obtained, such as a high molal polypropylene glycol or the products obtained in the mannerherein described one does not obtain a single derivative such as HOiROMH in which n has one and only one value, for instance, 14, 15, or 16, or the like. Rather, one obtains a cogeneric mixture of closely related or touching homologues. These materials invariably have high molecular weights and cannot be separated from one another by any known procedure without decomposition. The properties of such mixture represent the contribution of the various individual members of the mixture. 011 a statistical basis, of course, n can be appropriately specified. For practical purposes one need only consider the oxypropylation of a monohydric alcohol because in essence this is substantially the 15 mechanism involved. Even in such instances where one is concerned with a monohydric reactant one cannot draw a single formula and say that by following such procedure one can readily obtain 80% or 90% or 100% of such compound. However, in the case of at least monohydric initial reactants one can readily draw the formulas of a large number of compounds which appear in some of the probable mixtures or can be prepared as components and mixtures which are manufactured conventionally. Simply by Way of illustration reference is made to the De Groote, Wirtel and Pettingill Patent No. 2,549,434, dated April 17, 1951, the application for which was copending with my copending application Serial No. 183,294 noted above.

However, momentarily referring again to a monohydric initial reactant it is obvious that if one selects any such simple hydroxylated compound and subjects such compound to oxyalkylation, such as oxyethylation, or oxypropylation, it becomes obvious that one is really producing a polymer of the alkylene oxides except for the terminal group. This is particularly true where the amount of oxide added is comparatively large, for instance, 10, 20, 30, 40, or 50 units. If such compound is subjected to oxyethylation so as to introduce 30 units of ethylene oxide, it is well known that one does not obtain a single constituent which, for the sake of convenience, may be indicated as RO(C2H40')30H. Instead, one obtains a cogeneric mixture of closely related homologues, in which the formula may be shown as the following, RO(C2H4O)1-.H, wherein n, as far as the statistical average goes, is 30, but the individual members present in significant amount may vary from instances where n has a. value of 25, and perhaps less, to a point where 12 may represent 35 or more. Such mixture is, as stated, a cogeneric closely related series of touching homologous compounds. Considerable investigation has been made in regard to the distribution curves for linear polymers. Attention is directed to the article entitled Fundamental principles of condensation polymerization, by Flory, which appeared in Chemical Reviews, volume 39, No. 1, page 137.

Unfortunately, as has been pointed out by Flory and other investigators, there is no satisfactory method, based on either experimental or mathematical examination, of indicating the exact proportion of the various members of touching homologous series which appear in cogeneric condensation products of the kind described. This means that fromthe practical standpoint, i. e., the ability to describe how to make the prodnot under consideration and how to repeat such production time after time without diificulty, it is necessary to resort some other method of description, or else consider the value of n, in formulas such as those which have appeared previously and which appear in the claims, as representing both individual constituents in which n has a single definite value, and also with the understanding that n represents the average statistical value based on the assumption of completeness of reaction.

however, is 15, assuming, as previously stated, that the reaction is complete.

The product de- 16 scribed by the formula is best described also in terms of method of manufacture.

PART

' Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, 'octyl alcohol, etc., may be employed as diluents. Miscellaneous solvents such as pine oil, carbon tetrachloride; sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of my process may be admixed with one 'or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well-known classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both 011- and water-solubility. Sometimes they'may be used in a form which exhibits relatively limited oil-solubility. However, since such reagents are frequently used in a ratio of l to 10,000 or 1 to 20,000, or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000 as in desalting practice, such an apparent insolubility in oil and water is not significant because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of my process.

In practicing my process for resolving petroleum emulsions of the water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One't'ype of procedure is to accumulate 9. volume of emulsified oil in a tank and conduct a batch treatment type of demulsification procedure to recover clean oil. In this procedure the emulsion is admixed with the demulsifier, for example by agitating the tank of emulsion and slowly dripping deniulsifier into the emulsion. In some cases mixing is achieved by heating the emulsion while dripping in the demulsifier, depending upon the convection currents in the emulsion to produce satisfactory admixture. In a third modification of this type of treatment, a circulating pump withdraws emulsion from, e. g., the bottom of the tank, and reintroduces it intoth'e top of the tank,the demulsifier being added, for example, at the suction side of said circulating pump. i

In a second type of treating procedure, the demulsifier is introduced into the well fluids at the well-head or at some point between the wenhead and the final oil storage tank,'by means 'of an adjustable proportioning mechanism or proportioning pump. O-rdinarily the 'flow of fluids through the subsequent lines and fittings sufiices to produce the desired degree of mixing of dernulsifier and emulsion, although in some 'instances additional mixing devices may be introduced into the flow system. In this general procedure, the system may include various mechanical devices for withdrawing free water, separating entrained water, or accomplishing quiescent clean or dehydrated oil. The amount being fed at such stage is usually 1:10.000, 111 15.000,

settling of the chemicalized emulsion. 'Heating devices may likewise be incorporated in any of theftreating procedures described herein.

Alt'l'iird type of application (down-the-hole) of ,deniulsifier' to emulsion is to introduce the demulsifier either periodically or continuously in dilutedor undiluted forminto the well and to allow it to come to the surface with the well fluids, and then to flow the chemicalized emulsion through any desirable surface equipment, such as employed in the other treating procedures. This particular type of application is decidedly j;tign 1with "acidification of calcareous oil-bearing strata, especially if suspended in or dissolved in the acid employed for acidification.

In all cases," it will be apparent from the foreig'oing description, the broad process consists simplyin introducing "a relatively small proportion I ofdemulsifier into arelativelylarge proportion .7 well-head where the eifiuent liquids leave the well. 1 This reservoir or container, which may vary from 5 gallons. to 50 gallons for convenience, is connected to a proportioning pump which injects the demulsifier drop-wis into the fluids leaving the well. Such chemicalized fluids pass through the flowline into a settling tank. The settling tank consists of a tank of any convenient size,

for instance onewhichwill hold amounts of tained.

.. cost.

1:20,000, or the like.

In many instances the oxyalkylated products herein specified as demulsifiers can be convenient- 1y used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mixing 75 parts by weight of an oxyalkylated derivative, for example, the product of Examplelfib with 15 parts by weight of xylene and 10 parts by weight of isopropyl alcohol, an excellent demulsifieris ob- Selection of the solvent will vary, depending upon the solubility characteristics of the oxyalkylated product, and of course will be dictated in partby economic considerations, i. e.,

As noted above, th products herein described n ay be used not only in diluted form, but also may be used admixed with some other chemical demulsifier. A mixture which illustrates -such combination is the following:

Oxyalkylated derivative, for example, the product of Example 182), 20%.

A oyclohexylamine salt of a polypropylated naphthalene monosulfonic acid, 24%; t

An ammonium salt of a polypropylated naphthalene monosulfonic acid, 24%;

A sodium salt of oil-soluble mahogany petroleum sulfonic acid, 12

A high-boiling aromatic petroleum solvent. V t t Isopropyl alcohol, 5%.

The above proportions are all weight percents.

PART 5 Previous reference has been made to other oxyalkylating agents other than propylene oxide,

such asethylene oxide. Obviously variants can be prepared which do not depart from what-is said herein but do produce modifications. Aniline or other suitable primary amine can be reacted with ethylene oxide in modest amounts and then iiuidproduced in 4 to .24 hours (500 barrels to ZQQQharrels capacity), and in.which there is a perpendicular -conduit from the top of the. tank to almost the very bottomso as to permit the incoming fluids topass from the top ofthe settling tank to the bottom, so thatsuch incoming fluids do not disturb stratification which takes place during the course of demulsification. The settling tank has, two outlets, one being below the water level to drain on the water resulting from demulsification or accompanying the emulsion as perature; for instance,

free water, the other being'an oil outlet at the top to permit the passage of dehydrated oil to a second tank,'being a storage tank, which holds pipeline or dehydrated oil. If desired, the conduit or pipe which serves to carry the fluids from the wellto the settling tank may include a section of pipe with bailies to serve as, a mixer, to insure thorough distributionwot the demulsifier throughout the fluids, or a'heate'r for raising the temperature of the fluids to some convenient tem- 10- F., or both 5 heaterandmixer.

Demulsificationprocedure is started by simply subjected to oxypropylation provided that the resultant:derivative is (co water-insoluble, '(b) kerosene-soluble, and j(cj). has present 15 to '80 alkylene oxide radicals. Needless to say, in order to have water-insolubility and kerosene-solubility the large majority must be propylene oxide. Other variants suggest themselves, as, for example, replacing propylene oxide by butylene id v .1

More specifically, one mole of anilin can be treated with 2, 4 or 6 moles of ethylene oxide and then treated with: propylene oxide so as to produce a water-insoluble, kerosene-soluble oxyalkylated aniline in which there are present 15 to 80 oxide radicals as previously specified. Similarly the propylene oxide can be added first and then the ethylene oxide, or random oxyalkylation can be employed using a mixture of the two oxides.

The compounds so obtained are readily esterified in the same manner as described in Part2,

preceding. Incidentally, the diolsfdes cribed in Part 1 or the modifications described therein-can be treated with various reactants such asglycide, epichlorohydrin; dimethy-l sulfate, sulfuric "acid,

- maleic anhydride, ethylene imine,-etcZ Ii -treated with epichlorohydrin or 'monochloroa'cetic acid the resultant product can be further reacted with a tertiary amine such as pyridine, or the like, to give quaternary ammonium compounds. If treated with maleic anhydride to give a total ester the resultant can be treated with sodium .bisulfite to yield a sulfosuccinate. Sulfo groups can be introduced also by means of a sulfating agent as "previously suggested, or by treating the chloroacetic acid resultant with sodium sulfite.

I "have found that if such hydroxylated compound or compounds are reacted further so as to produce entirely new derivatives, suchv new derivatives have the properties of the original hy- Having thus described my invention, what I 5 claim as new and desire to secure by Letters Patent, is:

'1. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the-emulsion to the action of a demulsifier including hydrophile synthetic products; saidhydrophile synthetic products being characterized by the following formula:

in which R' is a hydrocarbon radical selected from the class consisting of phenyl radicals, methylphenyl radicals, and benzyl radicals, and n and 'n are whole numbers with the proviso that n plus n equals a sum varying from to 80; n" is a whole number not over 2 and R is the radical of a polycarboxy acid OOOH 0 0 011),. in which n" has its previous significance with the further proviso that the parent dihydroxy compound prior to esterification be water-insoluble and kerosene-soluble.

2. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demul- 'sifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula:

in which R. is a hydrocarbon radical selected from the class consisting of phenyl radicals,

methylphenyl radicals, and benzyl radicals, and

n and n are whole numbers with the proviso that n plus n equals a sum varying from '15 to 80; n". is a whole number not over 2 and R. is the radical of a polycarboxy acid i inwhich n" has its previous significance; said 'polycarboxy acid having not more than 8 carbon atoms; with the further proviso that the parent fdihydroxy compound prior to esterification be water-insoluble and kerosene-soluble.

3. A process for breaking petroleum emulsions of the water-in-oil type characterized by sub- -droxylated compound insofar that they are effectiv e and valuable demulsifying agents for resolution of water-in-oil emulsions as found in the petroleum industry, as break inducers in do -tr treatment of sour crude, etc.

'jectingthe emulsion to the action of a demulsifier including hydrophile synthetic products;

said hydrophile synthetic products being characterized by the following formula:

in which R is a hydrocarbon radical selected from the class consisting of phenyl radicals, methylphenyl radicals, and benzyl radicalsyand n and n are whole numbers with the proviso .that'n plus n equals a, sum-varying from 15 to'80 and R. is the radical of a dicarboxy acid OOOH said dicarboxy acid having not more than '8 carbon atoms; with the further proviso that'the parent dihydroxy compound prior to esterification be water-insoluble and kerosene-soluble.

4. A process for breaking petroleum emulsions of the water-in-oil type characterized by'subjecting the emulsion to the action of a demulsifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula:

in which n and n are whole numbers with the proviso that 11. plus 1!. equals a sum varying from 15 to and R is the radical of a dicarboxy acid COOH R coon said dicarboxy acid having not more than 8 carbon atoms; with the further proviso that the parent dihydroxy compound prior to esterifica- MELVIN DE GROOTE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,507,560 De Groote et al. May 16, 1950 2,514,399 Kirkpatrick et al. July 11, 1950 2,562,878 Blair Aug. 7, 1951 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING HYDROPHILE SYNTHETIC PRODUCTS; SAID HYDROPHILE SYNTHETIC PRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA: 